1. Field of the Invention
This invention relates to controlled-release, drug-delivery systems for effecting the desired controlled-release of pharmaceutical medicaments in a topical application.
2. Description of the Prior Art
In the pharmaceutical industry much work has been devoted during recent years to improving the effectiveness, safety and practicality of administered drugs. Accordingly, this invention is specifically directed toward the goal of prolonging the release of a topically applied drug over a period of several hours. Such a prolonged release has the following advantages: peak blood levels of the drug which sometimes represent toxic levels are avoided since not all the drug is released at the same time; secondly, drug concentrations in the blood are maintained for a longer time within the therapeutic range, thereby increasing the overall effectiveness of the drug and reducing the overall dose-size necessary for treatment; thirdly, drugs which would have to be taken in conventional form several times daily for the treatment of chronic diseases, can be topically applied in once or twice-a-day dose forms, which are safer and more convenient for the patient.
Accordingly, it is an object of this invention to provide a controlled-release, drug-delivery composition for topical application comprising an effective amount of a pharmaceutical medicament in an emulsion containing polymer.
Another object herein is to provide a controlled-release, topically appliable drug-delivery, emulsion composition which includes the polymeric reaction product of a non-aqueous, heterogeneous polymerization process for making vinyl polymers using an oil solvent.
These and other objects and features of the invention will be made apparent from the following description of the invention.